Electrical contact spring assembly



April 3, 1956 s. D. VlRE'N ET AL 2,740,871

ELECTRICAL CONTACT SPRING ASSEMBLY Filed April 14, 1952 2 Sheets-Sheet l j UUE F/g' 2 4 7 l/ l/r f April 3, 1956 s. D. VIGREN ETAL 2,740,871

ELECTRICAL CONTACT SPRING ASSEMBLY Filed April 14, 1952 2 Sheets-Sheet 2 United States Patent C) ELECTRICAL CONTACT SPRING ASSEMBLY Sten Daniel Vigren, Stockholm, Walter Otto Wilhelm Broberg, Nynashalnn, and Rolf Albin Zander, Stockholm, Sweden Application April 14, 1952, Serial No. 282,112

7 Claims. (Cl. 20o- 166) This invention relates to contact-spring assemblies for electric switching devices having both stationary and movable contact springs and wherein the movable contactsprings are operated under the control of a unitary stud common to all of the movable springs of the assembly.

In designing a contact-spring assembly of this type it is desirable to minimize the number of different component parts included in the assembly and to so arrange the assembly that all contact-functions required can be performed by these parts. Thus the insulating plates between the springs should be interchangeable, the number of ditterent types of contact-springs should be limited, the thickness of the springs should be the same for all contactsprings and all contact-springs should be provided with the same type of contacts. Furthermore, the operatingstud should be designed so as to be adaptable to any desired contact-functions. The mode of operation of the contact-functions should be uniform, and the counterpressure upon completed closing-operation should be independent of the position of the operating-stud.

In some known types of contact-spring assemblies, the

contact-functions, which are intended to perform closingoperations on the upward movement of the operatingstud are arranged in such a way that the stationary contact-spring resting on the upper surface of a tooth of the supporting-stud will determine the contact-pressure when the closing-operation is completed. On completing the closing-operation, the stationary contact-spring has to be lifted a small distance above the tooth in order to ensure an eiiicient contact, and for this reason the groove adjacent to the tooth has a width considerably greater than the thickness of the contact-spring.

It has been found that, when the contacts of the movable contact-spring strike against the contacts of the stationary contact-spring, the latter will bounce upwards and disengage its contacts from the contacts of the movable contact-spring. There is nothing that prevents the xed contact-spring from bouncing since, as already mentioned, the latter has to be somewhat movable and resilient in order to produce the desired contact pressure. These bounces, which are repeated several times during a closingoperation cause sparks and destroy the contacts.

In contact-functions which are break-operations on the upward movement of the operating-stud, the movable contact-spring causes the contact-pressure by resting with its contacts upon the contacts of the stationary contactspring. The stationary contact-spring rests upon the upper surface of a tooth of the supporting-stud. At the break-operation, the movable contact-spring is lifted upwards, by the upward movement of the operating-stud, by a tooth of the operating-stud. When a break-contact is in a non-operated condition there is a small air-gap between its movable contact-spring and that tooth of the operating-stud which is intended to actuate the movable contact-spring. This small air-gap will ensure that the movable contact-spring, While abutting with its contacts against the contacts of the stationary contact-spring, does not touch the tooth of the operating-stud.

ICC

On the downward movement of the operating-stud, the contacts of the break-contact will be closed again, i. e., the break-contact acts as a make-contact.

Thus on closure of the break-contact, the movable contact-spring effects the contact-pressure and the xed contact-spring will have a fixed position since it abuts with pressure against the upper surface of a tooth of the supporting-stud.

Although in this case the stationary contact-spring is prevented from bouncing through its abutment against the associated tooth of the supporting-stud it will be understood, that this manner of contact closure generally shows a much less tendency to bounce than is the case in the manner of contact closure used in the described makecontacts.

In the make-contacts the movable contact-spring is` forced towards the stationary spring by the operating-stud and the force with which it strikes the stationary spring is largely due to the kinetic energy of the entire armature system. Since in a break-contact the movable spring is tensoned so as to perform its contact closure movement by its own spring tension and the task of the operatingstud is merely to release the movable spring so as to move against the cooperating stationary spring, the force with which the movable spring hits the latter is merely determined by the relatively small spring-tension and weight of the movable spring.

This is the main and basic reason why in known devices the contact-closures of break-contacts are generally more free from vibration than the contact-closures of makecontacts.

It is an object of this invention to provide contactspring assemblies, which may be composed of different optional contact units or combinations by means of a small number of different basic elements comprising stationary and movable contact-springs and an operating-stud having teeth, shoulders or the like for the operation of the movable springs, in which not only the break-contacts but also the make-contacts are arranged to give a contactclosure substantially free from vibration according to the release principle outlined above.

The invention is foremost characterised by the fact, that said teeth, shoulders or the like of the operating-stud form pairs of opposing abutting-surfaces for each pair of neighboring contact-springs, the pairs of contacts-springs being disposed with even spacing, and that the movable contact-springs forming part of make-contacts as well as break-contacts co-operate with abutting-surfacesl of the operating-stud that are directed from the respective associated stationary contact-springs and are tensioned so as to tend to move towards the respective associated xed contact-springs under their spring-tension.

The following is a description, by way of example, Vof contact-spring assemblies according to the present invention, reference being made to the accompanying drawings, wherein:

Figure l shows a contact spring assembly according to the invention in side elevation.

Figure 2 shows the same contact spring assembly in end elevation.

Figure 3 shows the same contact spring assembly as seen in plan.

Figure 4 shows the same contact spring assembly in cross section along line A-A in Figure l.

Figure 5 shows part of the Contact spring assembly according to Figure 1 with the difference that the two lowest springs have been inter-changed,

Figure 6 shows the same contact spring assembly as Figure l except that the operating-stud is disposed transversally and has two teeth for each movable contact spring.

Patented Apr. 3, 1956 Figure 7 shows the last-mentioned contact spring assemb1y inl end elevation.

Figure 8 shows one of the fixed contact springs used in the embodiments illustratedin plan view.

`Figure9 'sliws'bne'ofth'e movable contact springs plnview. l ,t Y .Y v

The contact spring assembly shown in Figure l is built up "o'f seven 'contact' springs'on a ixedmsupprting bridge 1"or'1'1 which a guiding plate 2' rests.l `The' guiding plate 2 guides v'the lower portion of averticall'y "movable op;v

The' operating'stud `3' and 'the supporting stud 4 are pressed vagainst fthemgu'idi'g plate by" the combined pressure and guiding spr gli "'"Sin'ce'the pressure land giiidingispring i3 is'forr'nlwith twoV tongues, 'a relatively iiXed'in'ner tongue to 'act'upon the supporting stud 4 and a'A movable outer tongueV to `act'""i'ipori'th'e operating stud 3, the operating stud'rnay'be' actuated by a 'lifting member without appreciably'atfecting tlie'pre'ssure Yonthe supporting stud. Y l

TheA contact spring assembly illustrated in Figure l comprises three Contact groups 'for performing three different contact functions. The particular one ofthe contact functions depends on the function which the'contact springs with their contacts 'will'perforrnon theupward movement of the operating stud t. It is evident that when the lifting stud after completion of its upward move-` ment moves downwards again', the functions of'thecontactsprings'willbe 'reversed'.v i l' y The contact'function/of the lowest contact spring assembly shown in Figure l is abreak contact.Y `When the. operating stud 3 isin V'non-'operated position thereis a small, air'gap between the upper surface of the movable tooth' 15. and the corresponding" movable lContact spring 12. This small air gap is necessaryfor the vsake ofy oontact, efficiency, becausev it 'must beensure'dfthat the con-, tact spring -does not abut against the upper'surfacefof the, tooth 1S, since otherwisel there would be a risk` that the. pressure of the Contact spring l2 would beentirely,y

or partially absorbed by the surface of1 the'tooth notiby, the contacts of 'contact' spring 6.y When the op-` erating stud 3 is operatedbyfa'lifting member, for iiistance an armature, andstudfmoveswupwards; the'upplsurface of the tooth will iirstpassl through themsmallv air gap between thevtootli .15"and'the'fiee end of'movable Contact spring i2 whereupon the toothi'duringfits upward' movement willmove thisv contact spring ilarid separate its contacts fromthefcontacts'lof the-'relatively stationary contact member 6l lri'other words va break is eiec'ted in the electricalv connctionbetween eoiitact springs6and12. 'y

The middle spring group contact function in the contact springassembly shown in Figurelis a'i/riake (Contact. As long as the operating stud is in iti-s lower, ciononoperated1 PQsition the underneath side of-V the tooth Avllt; holds the movable contact spring 1l in such a lposition that anair gapexists between the contacts oftthis relativelymovable spring 11 and the contacts of4 the. fixed` spring 7. The movable contactspringllA abuts` against the underneath side of 'the'tootli lwith a pressure. at,

least asgreat as the contactpressure whichit is intended to exert. When theoperating kystud movesupwardsunder 1,1, the pressure of which is directed in thedirecti on of I control of the lifting member, the movable.contacttspiingv the space that initially separates them from the contacts of the fixed Contact spring 7. When the contacts of the movable contact spring touch the contacts of the stationary contact member 7, the movement of the movable contact spring 11 will cease, while the movement of the actuating stud continues until a small space has been formed between the underneath side of the tooth 16 and the movable contact `spring il, rI This space assures the maintenance of desired Contact pressure in the same manner as described above in connection with the break Contact.

The contact function of the uppermost contact group in the contact spring assembly shown in Figure l is a breakbefore-make Contact. The number of springs comprised in a break-before-make contact is at least three as shown in Figure l and includes in this case a fixed contact niember 8 having contacts on both sides and two movable contact springs 9 and l0 located one on each side of the xed contact member S. The contact member 8 forms together with the lower movable Contact spring lil a make contact and with the upper movable Contact spring a break Contact. When operating as a break-beforemake contact, the lower movable Contact spring l0 strikes with its contacts against the contacts ofthe fixed contact member 8 afterl the upper movable contact spring 9 has broken the contact with the fixedcontact spring.

The inode of operation of the functions of the breakbefore-make Contact is analogous to the break and make functions described above.

A break-before-make contact can be altered to a makebefore-break Contact in the following manner:

rThat portion of the lowermovable contact spring 10; which is'porsitioned between its contacts and the operating stud 3 is bent downwards, Then the contacts of the lower movable contact spring will be brought nearer to the contacts ofI the fixed contact spring. The closure will thus occur within a shorter time. The corresponding portion of the upper movable contact spring 9 is preferably bentl upwards. The space between the yupper sui-.face of a tooth lv of* the operating stud 3 and the upper movable contact spring 9 is thenincreased. Duringf the upward,v movement vof the operating stud,l the toothy will-'reach the upper contacty spring 9v later and consequently the break will also occur later. The adjustment shouldl be carriedy out so that the make occurs before the break.. Whenthus operating as a make-beforebreak, the lowei movable contact spring lil hits with its contacts against the contacts of the fixed, contact member 8 before the upper movable contact spring 9 breaks, the contact withy the xed contact member 8.

A make-befoi'e-break operation may also be obtained by increasing the height ofthe contacts ofthe fixed c ontactrmernber'.4 The "spacing between the contacts ofthe make contact-will thenrdecrease, and the make willpocc-uiearlier while the break will occur later, because the distance between the upper side ofthe tooth 17- andv thepniovable contact spring 9has increased due to the increasein height of the contacts on the fixed contact spring.

When the lifting memberisrestored, the operating stud returns to its initial position substantially through the action` of the outer tongue of the pressure and guidingl spring 13, which yieldirigly'urges the operating stud towards 'the lguidingplate 21S yThe operation ofthe contact groupsis then reversed, the lower contactgroup acting as a ineke v =gntficttfhgmiddle Contest group asabreak.. Cntat and. fliafuppet cantas@ group .as a. make-beforebrefak centatwithfthe malte attire-maand the` break at the, betteln Whe-1i @met Closures acsgmnany the upward, uitwement of the operating, stud,A Ttheiipper` side of a.. tooth does; not-lift the` movablefcontaot,springs llilaricl 1 1, butthe lavable- CQntact Springs Preis dile t0 their tensioni against the Uniti-integratie @tithe tenutasi-fellow due: te. the, nidi` tension, that Siusi upwards 1 until they, arg.

stopped by the contacts off-the-xedcontactspringst A:

similar operation will occur with 'regard to the break contacts when the stud moves downwards and the break contacts are closed, the movable contact springs of the break contacts then following instead the upper side of the tooth. Thus after the closure is completed the contact pressure will be independent of the continued movement and position of the operating stud.

Figure 5 shows a modification of the lowermost contact spring group assembly according to Figure l. The movable contact spring 12 has changed position with the xed contact spring 6 and forms together with the latter a make contact instead of a break contact as in Figure l. in Figure 5 the movable contact spring abuts against the underneath side of the tooth 15. As will be understood from the above, the movable contact spring will be guided on its upward movement by the upper side of a tooth if the contact function is a break. If the contact function is a make, the movable contact spring will be guided by the underneath side of the tooth. As will fur ther appear from the figure, a break contact will become a make contact and vice versa if the contact springs in a contact function are interchanged and the movable con tact springs of the contact function are guided by the same tooth. This guiding action is achieved by a dis placement of the teeth of the operating stud in relation to those of the supporting stud.

Figures 6 and 7 show a contact spring assembly similar to that of Figure l having fixed Contact members 6--8I and movable Contact springs 9-12. A modified operating stud 18, however, has been substituted for the operating stud 3. The stud 3 in Figure l has its teeth turned inwards to the spring assembly, one tooth controlling both the contact-carrying tongues of each movable contact spring. The operating stud 18 shown in Figures 6 and 7 is provided with two teeth for each movable contact spring and is inserted between the contact-carrying tongues of the movable Contact springs 9-12 and is positioned so that the two tongues of each movable contact 'spring will each be controlled by an individual stud tooth. Then the spacings between the movable contact. springs and the teeth of the operating stud can be viewedV more conveniently from the front end of the spring assembly. in the Contact spring assembly according to Figures l and 6 there are provided teeth, both on the operating stud and on the supporting stud for all possible arrangements of movable contact springs and stationary contact members within the contact spring assembly.

in the arrangement shown in Figs. 6 and 7, it may be desirable to provide the supporting stud 4 with pairs of laterally extending teeth like operating stud 18 in order to obtain a better support for the iixed contact members.

rihe regular relation between make and break functions is made possible by a displacement of the teeth of the operating stud with respect to the teeth of the supporting stud.

in the design of the operating and supporting studs, the spacings between the teeth of the studs must agree with the spacing between the contact springs or the contact functions in the Contact spring assembly. It is not possible to arrange the operating and supporting studs so that the upper sides of their teeth are on a level with each other. In Figure 8 a fixed contact spring is shown having a slot at the contact end, in which the supporting stud lits, and a twin contact with two contactsV 36. in Figure 9 a movable contact spring is shown having a slot 37 through which the supporting stud may pass without actuating the spring.

in the embodiments described above all contact operations, makes as well as breaks, have been performed in accordance with the principle that the respective movY able contact spring etiects the closure of contacts by movement due to its own spring tension irrespective of whether the contact closure occurs on the operation or release of the relay.

6 We claimf i k 1. A contact spring assembly comprising' base inem# ber, spaced generally parallel stationary contact members and movable contact springs for circuit making and breaking cooperation with each other disposed in at least one group, fixing means for xing one end of each of said movable contact springs with relation to said base member on any of a number of predetermined, substantially evenly spaced levels above said base member so as to hold the movable contact springs in piledup relation on the same and leave the other end of each movable contact spring free to move in a direction substantially perpendicular to the longitudinal direction of the movable contact springs, said fixing means comprising means for holding each of said stationary contact members on any of a number of predetermined levels, not occupied by movable contact springs, which levels substantially coincide with said first-mentioned levels, and in engageable relation with said movable contact springs, each of said Contact springs being pre-tensioned so as to tend to flex its free end into engagement with its cooperating stationary contact member and being situated on one side of its cooperating stationary contact member when forming part of a make contact group and on the other, opposite side of its associated stationary contact member when forming part of a break contact group, the contact spring assembly further comprising an operating, comb-like stud member, means for movably supporting the operating stud member at the free ends of the movable contact springs to be slidable between a non-operated and an operated position, the direction of said sliding being substantially perpendicular to the longitudinal axis of the movable contact springs, said operating stud member having evenly spaced teeth thereon for engaging the free ends of said movable contact springs, a tooth adapted for the individual actuation of a single movable contact spring being provided substantially in `alignment; with each of the spaces between said first-mentioned levels at least one of said teeth controlling a make contact group and at least one other of said teeth controlling a break contact group, and each tooth defining two opposed surfaces extending substantially normally to the direction of said sliding, that surface of each tooth controlling a make contact group which is turned against the direction of said sliding on operation of the said stud being adapted to engage the free end of the movable contact spring forming part of the respective cooperating make Contact group and the surface of each tooth controlling a break Contact group which is turned in the direction of said sliding on operation of the said stud being adapted to engage the free ends of the movable contact spring forming part of the respective cooperating break contact group.

2. A contact spring assembly according to claim l, in which said movable contact springs are slotted at their free ends to form twin contacts and said operating stud member has the shape of a at strip provided with teeth arranged in pairs opposite to each other, said operating member extending through the slots of the movable contact springs and having its teeth projecting perpendicularly to the longitudinal axis of the movable contact springs and in engageable relation with the latter.

3. A contact spring assembly according to claim l, said assembly including a transfer contact group, said transfer contact group comprising a stationary Contact member and two movable contact springs disposed on opposite sides of said stationary contact member, each of said movable Contact members being so pretensioned as to tend to ex its free end into engagement with said stationary contact member, said movable contact members being further so disposed with respect to each other to be selectively releasable to engage said stationary contact member by engagement with opposed surfaces on two adjacent teeth of said comb-like stud member.

4. A contact spring assembly which is made; oft standardized cempOrients` permitting; maximum variation in switliina contact arrangements with a minimum; num:- ber of;` st211.1dardized.parts,A Comprising; abase means, and.:

break Contact sett; each of saidr movable contact elements.

being'. biased towards its cooperatingl fixed Contact clement sopas to normally make, contact therewith; a comblike. operating st ud. member having substantially evenly spaced teeth., thereonftwith at least one tooth disposed between;l each pair of adjacent contact elements, each of, said teethy lia-ving-L two.- opposed; spaced operating surlaces` adapted to engage and operate a movable contact element, and one of said surfaces engageable with one of said movable contact elements to displace it from` its cooperatingiixed Contact element in a direction opposite to` normal bias of the movable element.

5. Ay contact spring; assembly as defined in claim 4, further comprising asupporting stud having notches withy the same spacing as the teeth on the operating stud, said` notches receivingl and holding the fixed contact leaves at some distance from their contact ends.

6. A contact spring assembly which is made of standardized components permitting,` maximum varia tion in switchingy contact arrangement with a minimum number of standardized parts, comprising: a base means and a` plurality of; non-conducting spacer members of substantially uniform thickness supported thereon in piled-up relation; a plurality of relatively xed Contact leanL springs each'.y supported;1 adjacentY one-i end-i thereof. between: afpair off; adiacenti. spacer."y members; a; plitralityy of., relativelvresilient mov-able; Contact: leaf,- springs; one.:

each cooperating @withf one l of: Said; iixed. springs; andv supplotted. adjacent;oneend"thereof between.y a pair oiaad;

jacentf spacers,,eachfof said movableI andxed contact.'

springs being mounted between adiffercnt set'ofy spacers in, similar piled-'up relation; each of said movable contact springsbeing biased towards itsv cooperating fixed contact springs@ as to normally make contact therewith; a comb-like operatingfstudy member having substantially evenly spaced teeth thereon with at least one,

Refer-ences Cited in the tile of this patent UNITED STATES PATENTS 2,279,811 Baker Apr. i4, 1942 2,282,687r Vigren et al. May l2, 1942 2,472,709 Knapp rune 7, 1949 2,582,131 iorgensen et al. Ian. 8, i952 2,612,367 Blomqvist Sept. 30, 1952 2,616,993 Koehler Nov. 4, 1952 FOREIGN i PATENTS 67,366'y Denmark Aug. 9, 1948 

